Constant lift jacking device



Jul 15, 1969 J. K. STEWART CONSTANT LIFT JACKING DEVICE Filed March 2l, 1966 2 Sheets-Sheet 1 Joy/v A. SVZ/MAT ATmPA A J July 15, 1969 J. K.STEIIWART 3,455,249

CONSTANT LIFT JACKING DEVICE Filed March 21, 1 966 2 Sheets-Sheet 2 wravme Jaw/v K smwpz United States Patent U.S. Cl. 104-7 1 Claim ABSTRACT OF THE DISCLOSURE A track lifting device comprising track engaging clamps mounted on the front of a track travelling vehicle, which clamps have track lifting motors connected to them for reaction against an anchorage adjacent the rear of the vehicle, the track lifting motors being continuousuly operated so that a continuous upward force is applied to the clamps to lift the track. A track level reference datum is provided by means of a high frequency beam transmitter, a beamreceiver means and a shadow board referenced to the track surface and located between the transmitter and receiver means, servo-control devices are operated by command signals from the receiver means to control the correcting operation of the lifting motors when the shadow board moves slightly above or below the datum.

This invention relates to a device for lifting rails, more particularly railway tracks, for the purposes of track levelling or gradding.

, Track levelling is normally effected by lifting a rail in regions of rail depression, introducingballast below the ties, and then tamping the ballast and it is known to provide levelling apparatus comprising a vehicle adapted to travel along the track the vehicle including apparatus for liftingthe track and forperforming the ballasting and tamping operations. Conventional apparatus of this type operates .in stepwisemanner along the track, the vehicle being stopped for each track jacking and tamping operation. Modern developments in track levelling techniques, however, along with persistent demand for higher speed operation,-has made desirable the provision of an apparatus with a very low time for the jacking cycle and which may even be capable of operating whilst it is moved continuously along the track.

v The disadvantatge of relatively slow stepwise operation is accompanied by the furtherdisadvantage that due to the intermittentlifting of the track, i.e. the lifting of the track at every tie to the required height, the accuracy of the finished tamped surface of the track is merely an average of the. various lifting operations and is not completely accurate, a Y

Thepresent. invention provides a track lifting device comprising aatrack travelling vehicle, track engaging clamp means mountedin front of said vehicle and movable along the track in. continuousgripping-engagement with each rail thereof; continuously operating lifting motors operatively connected to the clamp means'and reacting against an anchorageat, or adjacent, the rear of the vehicle; means forproviding a track levelreference datum and for auto matically-controlling the -action of the'lifting motors including a high frequency-beam transmitter; beam receivingmeans, a shadowlboard referenced-to the track surfaceand located between the transmitter and the receiving means and servo means subject to command signals from said ,receivingmeans for controllingthe operation of said lifting motorgwhereby to increase the lifting action of the lifting motors in response to a small differential movement of the shadow board below the reference datum and to decrease the lifting action of the lifting motors in response to a small differential movement of the shadow board above the reference datum.

Suitably the clamps comprise electro-magnets slidable along the surface of the rails. The means for applying an upward force to the clamps may suitably comprise a linkage and continuously acting lifting motors connected to the clamps and which react against and anchorage at or adjacent the rear of the carriage means being provided for controlling the action of the lifting motor. The anchorage at the rear of the carriage may be provided by means of clamps or counterweight disposed at the rear of the vehicle, the clamps being adapted to grip the track and be movable therealong. The clamps may again be electro-magnets and the counterweight may suitably be on the rear of the vehicle, in order to avoid the rear of the vehicle pivoting about the wheels at the front of the carriage asa track lifting force is applied to the front clamps. The linkage from the lifting motor to the anchorage at the rear of the carriage and the clamps at the front of the carriage may suitably be either a cable or a hydraulic linkage.

In the preferred embodiment of the present invention the vehicle is provided with a rigid structure which projects forwardly of the front Wheels the clamp means being supported on said structure, and the vehicle having sufficient weight behind the front wheels to provide a reaction force against which the track lifting force may work.

The clamp means may take the form of mechanical clamps adapted to grip the rail as the vehicle travels therealong, or may be electromagnet grippers with automatic flux control means.

The disadvantage of stepwise track lifting is overcome by the present invention and a highly accurate surface is obtained as the lift thereon is performed at an infinite number of points (i.e. continuously).

The operational speed obtained by the present invention is very high since, as the track is jacked continuously in infinite increments, when the vehicle stops to perform a tamping operation, the track already has been lifted to the required height and thus the time loss at the stop is merely the time occupied by the tamping operation itself.

According to another aspect of the present invention, it is contemplated that, in addition to the continuous lifting operation, a continuous tamp-ing operation is also provided. By the combined features of continuous lifting and continuous tamping, the present invention provides a tamping and jacking vehicle capable of continuously moving along the track being tamped, there being no need to stop the assembly over any particular tie of the track to either tamp it or jack it. T 0 enable the continuous tamping operation to be performed it is necessary to provide tamping heads which are capable of movement relative to the vehicle chassis so that they may perform their tamping function whilst the vehicle is moving slowly forwardly.

The following is a description by Way of example of certain embodiments of the present invention reference being made to the accompanying drawings in which:

FIGURE .1 is a schematic representation of a tamping machine diagrammatically showing the constant track lifta set of rear wheels 14, and is arranged for track travel under its own propulsion. Mounted on the vehicle are a plurality of tamping systems 16, 17. The tamping systems are conventional tamping heads comprising pairs of tamping units 19 and 20 mounted over each rail of the track on frames for up and down reciprocation relative to the vehicle so that the tamping bars of the tamping heads may penetrate the ballast and compact the ballast beneath the ties. In FIGURES l and 2, only the left hand tamping heads of the tamping systems are seen and it is to be understood that the tamping systems also include similar tamping heads on the other side of the vehicle for tamping the ballast beneath the other rail of the track. In the embodiments illustrated in FIGURES 1 and 2, the tamping systems 20 are shown mounted for longitudinal movement, on, and relative to the chassis of the vehicle 10, each system being provided with a suitable reciprocating motor on the vehicle, e.g. a hydraulic ram, capable of moving the tamping system relative to the chassis. Each tamping system is provided with its own tie sensing means which may suitably comprise a spring loaded position sensing finger such as disclosed in Canadian Patent No. 646,048. The sensing means are set in connection with a conventional control circuit so as to actuate the tamping system after the sensing finger has contacted and passed over a preselected number of ties, depending on the spacing of the tamping heads. Thus, the timing may be such that the tamping system 16 tamps the even numbered ties whereas the tamping system 17 tamps the odd numbered ties. By this embodiment, it is possible for the vehicle to continuously move along the track while the tamping systems operate continuously, the tamping systems longitudinally sliding relative to the vehicle and being arranged, on completion of a tamping operation, to be returned by their hydraulic rams to their correct relative position on the vehicle whereafter they proceed to tamp the ties therebeneath which due to the spacing and setting is automatically the correct tie. In the assembly described the tamping systems may be suitably biased to their correct relative positions by stops on the vehicle.

It is to be understood that whilst the device as shown in FIGURES l and 2 each show multiple tamping systems moved relative to the tamping vehicle, the continuous lifting feature which forms the basis for the present invention could be effected on a device having several more movably tamping systems, or on a device in which the front tamping device is not movable and wherein the vehicle has to briefly stop for the completion of the tamping cycle of the front system, on indeed, equally well on a conventional tamping vehicle having fixed tamping heads, which conventional vehicle would, of course have to stop its forward movement to permit a tamping operation.

The continuous lifting device according to the present invention, comprises, for each rail of the track, a clamp means C positioned in front of the vehicle and connected through the linkage L and a track lifting motor M to an anchor A. The clamp means C, and in the embodiment illustrated in FIGURE 2, the anchorage means A also, may comprise an electro-magnet. Preferably the electro-magnets are provided with automatic flux control means for example such as set out in co-pending British application 3,268/ 65. In that application there is described a pressure transducer arranged in a motor M, which pressure transducer senses the load applied at an electromagnet and controls the flux density available at the electro-magnet in direct proportion with the load thereon whereby to maintain the electro-magnet C in weight bearing engagement with the rails R whilst providing that no more flux than is necessary is made available. In this fashion the friction between magnet and rail when the vehicle is in motion, is greatly reduced.

In the embodiment shown in FIGURE 1 (and as will be seen, also with the embodiment of FIGURE 3), the

anchorage A comprises a counterweight mounted on the rear of the vehicle. It will be clear that the anchorage must be sufllciently powerful to exert more than equal and opposite force to that applied by the electro-magnets C, otherwise the vehicle, instead of lifting the track would tip forward. The linkage L may suitably comprise a cable, which in the case of FIGURE 1 passes over pulleys 25 and 26 and connects to the piston rod 27 of a hydraulic motor 30 which, in this example, constitutes the lifting motor M. (It will be further understood that an electric motor driven Winch could be used in place of a hydraulic motor 30, or for that matter, an air motor, or any other suitable arrangement.) The cylinder of the hydraulic motor 30 is welded to a stanchion 31 so that it is in fact secured on the chassis.

In the case of the device as shown in FIGURE 2, a long extension of the cable L1, is attached to the other end of the piston rod 27' and passes over pulley 35 and pulley 36 which is spaced well behind the vehicle on an extension of the frame, to the electro-magnet A which forms the anchor. It will be appreciated that it is necessary to space the magnets A well behind the vehicle so as to minimize the required reactions whereby to avoid disturbing the already established track surface.

The motors M, when operating, are always arranged to exert a lifting force on the magnets C to take the weight of the track immediately in front of the vehicle. That is to say, there is suflicient upward force exerted on the magnets C so that the track immediately ahead of the vehicle is lifted very slightly from its bed and is maintained in a floating condition. In order to correct track depressions the motors M are caused to exert a greater lifting force than is necessary merely to cause the track to float so as to lift the track out of its depression. Conversely, the motors M are caused to exert a lesser lifting force on the magnets C, when the magnets C encounter the unusual condition of a higher than normal point on the track, as will become apparent hereinafter.

The lifting action of the motors M may suitably be controlled electrically from a conventional infra-red radiation surveying system, for example, a surveying system such as described in Canadian Patent 650,557. In such a system a satellite car S which is provided with its own prime mover, precedes the tamping vehicle 10 along the track and projects a cone like beam of infra-red radiation from the projector P towards a receiver R over the grade rail of the track. A shadow board 40 positioned in the beam between projector and receiver and mounted on its own rail engaging wheels 41, provides a rail condition sensing device. The shadow board 40 is connected to the vehicle 10 and pushed thereby along the track. The receiver R and an associated conventional electrical circuit may be suitably arranged such that a preselected quantity of received infra-red radiation may be considered as a reference datum. Now when the shadow board 40 sinks into a depression in the track, the receiver R receives a greater quantity of projected radiation from the projector P than when the shadow board was on level track and was shadowing out from the receiver all but the quantity of radiation considered as datum. This increase in radiation level can be used, in a conventional fashion, to send a command signal to a servo valve to operate the motor M to increase the lift at the electro-magnet C. As the electro-magnet C lifts the grade rail with the shadow board 40 thereon, the intensity of the received radiation at the receiver R drops, since the shadow board interferes with the projected beam. Should the shadow board be lifted above the datum position, the receiver R will receive less than the datum radiation value and in conventional fashion a signal will be generated to operate the servo valve to control the motor M to decrease the,

lift at the electro-magnet C so that the track will be restored to datum level. The differential between the quantities of received light which control the operation of the motor M may be arranged to be very small. It is to be understood the control of the lifting of the other rail of the track may be by any suitable form of cross level sensing device.

In a preferred form of the invention, two receivers are provided, one receiver over each rail of the track and two shadow boards 40, one for each rail are positioned in the line of radiation transmitted from the projector P, the receivers are mechanically linked together to a gravity sensing device which ensures that the receivers are always maintained at the level position. The receiver R over the left-hand rail of the track is arranged to control the action of the left-hand electro-magnet C and the lefthand motor M and the right-hand receiver over the righthand rail of the track is arranged to control the righthand electro-magnet and its associated motor.

FIGURE 3 shows a further alternative in which the electro-magnets C are mounted on a rigid structure 30, 31, the motor M being directly coupled to he electro-magnet for vertical reciprocation thereof. The structure 30, 31 may form a rigid frame extension of the vehicle chassis, or may be in the form of a rigid trust pivotally mounted on a trunnion on a concentric extension of and outside the front wheel hub (one truss being provided on each side of the vehicle outside its chassis). If the latter arrangement is provided the motor for each truss may be located on trunnions on extensions of the rear wheel hubs, which motor M act to raise and lower the electromagnets C by pivoting the trusses about the front trunnions.

What I claim as my invention is:

1. A track lifting device comprising a track travelling vehicle, track engaging clamp means mounted in front of said vehicle and movable along the track in continuous gripping engagement with each rail thereof; continuously operating lifting motors operatively connected to the clamp means and reacting against an anchorage at, or adjacent, the rear of the vehicle; means for providing a track level reference datum and for automatically controlling the action of the lifting motors including a high frequency beam transmitter, beam receiving means, a shadow board referenced to the track surface and located between the transmitter and the receiving means and servo means subject to command signals from said receiving means for controlling the operation of said lifting motors, whereby to increase the lifting action of the lifting motors in response to a small differential movement of the shadow board below the reference datum and to decrease the lifting action of the lifting motors in response to a small differential movement of the shadow board above the reference tatum.

References Cited UNITED STATES PATENTS 2,478,535 8/1949 Kershaw 104--7 3,153,390 10/ 1964 Plasser et al. 104--7 3,301,198 1/1967 Bick 104-7 3,274,952 9/1966 Fekete 104-7 3,363,582 1/ 1968 Plasser et a1 1047 FOREIGN PATENTS 1,128,627 8/ 1956 France. 1,419,536 10/ 1 France.

ARTHUR L. LAPOINT, Examiner RICHARD A. BERTACH, Assistant Examiner 

